They're Essential. Every beach trip deserves a soundtrack. Be a hero and bring the tunesmith the Islabomba Beach Sounds. Requires x 4 AA batteries (not included). Works with any smart phone and tablet. Bluetooth wireless technology. MP3 speaker and AM/FM Stereo 2 band radio receiver. High output power and low distortion. Master and base volume control. Aux-in audio jack (connection cable included). Micro USB DC Jack. Play music off your device or off the AM/FM tuner. Sand and water resistant.